Method for manufacturing biomass based fuel configured to reduce a chemical and/or mechanical effect of flue gas on heat transfer surfaces

A method for manufacturing biomass based fuel, the method comprising:

• providing biomass into a reactor;
• providing steam into the reactor;
• maintaining said biomass and said steam simultaneously in the reactor, in a pressure of at least 10 bar(a) and at a temperature from 180° C. to 250° C. for at least 2 minutes;
• decreasing the pressure in the reactor and/or conveying biomass out of the reactor such that the pressure of the environment of the biomass decreases below 5 bar(a), to produce steam-exploded biomass;
• and
• adding some combustion additive to the biomass and/or the steam-exploded biomass,
• wherein:
• the combustion additive either (a) is selected from a group consisting of aluminium silicates, chalk, clay, dolomite, magnesium carbonate, coal fly ash, aluminium sulphate, mono calcium phosphate, dicalcium phosphate, calcite, bauxite, bentonite, bauxite, emalthite, gibbsite, hectorite, halloysite, and sulphur, or (b) comprises at least one of calcium, magnesium, potassium and phosphorus;
• and
• either:
• (c) at least some of the combustion additive is added to steam-exploded biomass after the reactor and the combustion additive is added to the steam-exploded biomass when the temperature of the steam-exploded biomass is at least 90° C., or (d) at least some of the combustion additive is added into the reactor.